The aim of this research is to extend our knowledge of adolescent-parent relationships, including adolescents' conceptions of rules, authority relations, and the social organization and social conventions of the family in relation to adolescent-parent conflict and the parental practices that promote conformity to rules or contribute to conflict and rebellion. It is proposed that 1) conflict with parents during adolescence stems from adolescents' rejection of parents' conventions and their attempts to redefine what are perceived to be arbitrary and relativistic conventional rules, and that accordingly, conflict occurs over the social-conventional rather than moral rules of the family or over different interpretations of the reasons for rules; 2) conflict is more likely during developmental phases in which adolescents question the necessity of adherence to rules and the dictates of those in authority; and 3) conflict is less likely in families where decisionmaking is democratic and where greater explanation is given for rules than in families where decisionmaking is autocratic and where little explanation is given for rules. Subjects in this study are 160 preadolescents and adolescents, 20 males and 20 females at each of the 5th, 7th, 9th, anad 11th grades, and their parents. Three methods of assessment will be used: 1) adolescents and parents will be administered the Home Rules Interview, used to assess conceptions of rules (and their domain), regulations, conventions, and authority relations in the family, the amount, frequency, and intensity of conflict regarding rules, the types of power and decisionmaking in the family, and the parental practices that are used to promote conformity to rules; 2) a videotaped Family Interaction Task, used to obtain behavioral indices of patterns of family conflict and dominance, and 3) the Social-Conventional Interview, a semi-structured clinical interview used to assess adolescents' developmental level of reasoning about social organization and social conventions. This research would contribute to our understanding of normal parent-child relationships during adolescence and of the types of family interactions that promote harmonious family functioning or that lead to conflict and rebellion. This would have applied significance in defining and promoting mental health among families with adolescents.